Channel state information reporting method, UE, base station and computer readable storage media

ABSTRACT

The present disclosure relates to a communication method and system for converging a 5 th -Generation (5G) communication system for supporting higher data rates beyond a 4 th -Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. Embodiments of the present disclosure disclose a method for CSI reporting at a UE and the corresponding UE.

TECHNICAL FIELD

The present disclosure relates to the field of wireless communicationtechnology, and in particular, to channel state information reportingmethods, a user equipment, a base station and computer readable storagemedia.

BACKGROUND ART

To meet the demand for wireless data traffic having increased sincedeployment of 4G communication systems, efforts have been made todevelop an improved 5G or pre-5G communication system. Therefore, the 5Gor pre-5G communication system is also called a ‘Beyond 4G Network’ or a‘Post LTE System’. The 5G communication system is considered to beimplemented in higher frequency (mmWave) bands, e.g., 60 GHz bands, soas to accomplish higher data rates. To decrease propagation loss of theradio waves and increase the transmission distance, the beamforming,massive multiple-input multiple-output (MIMO), Full Dimensional MIMO(FD-MIMO), array antenna, an analog beam forming, large scale antennatechniques are discussed in 5G communication systems. In addition, in 5Gcommunication systems, development for system network improvement isunder way based on advanced small cells, cloud Radio Access Networks(RANs), ultra-dense networks, device-to-device (D2D) communication,wireless backhaul, moving network, cooperative communication,Coordinated Multi-Points (CoMP), reception-end interference cancellationand the like. In the 5G system, Hybrid FSK and QAM Modulation (FQAM) andsliding window superposition coding (SWSC) as an advanced codingmodulation (ACM), and filter bank multi carrier (FBMC), non-orthogonalmultiple access (NOMA), and sparse code multiple access (SCMA) as anadvanced access technology have been developed.

The Internet, which is a human centered connectivity network wherehumans generate and consume information, is now evolving to the Internetof Things (IoT) where distributed entities, such as things, exchange andprocess information without human intervention. The Internet ofEverything (IoE), which is a combination of the IoT technology and theBig Data processing technology through connection with a cloud server,has emerged. As technology elements, such as “sensing technology”“communication and network infrastructure” “ ” “ ” have been demandedfor IoT implementation, a sensor network, a Machine-to-Machine (M2M)communication, Machine Type Communication (MTC), and so forth have beenrecently researched. Such an IoT environment may provide intelligentInternet technology services that create a new value to human life bycollecting and analyzing data generated among connected things. IoT maybe applied to a variety of fields including smart home, smart building,smart city, smart car or connected cars, smart grid, health care, smartappliances and advanced medical services through convergence andcombination between existing Information Technology (IT) and variousindustrial applications.

In line with this, various attempts have been made to apply 5Gcommunication systems to IoT networks. For example, technologies such asa sensor network, Machine Type Communication (MTC), andMachine-to-Machine (M2M) communication may be implemented bybeamforming, MIMO, and array antennas. Application of a cloud RadioAccess Network (RAN) as the above-described Big Data processingtechnology may also be considered to be as an example of convergencebetween the 5G technology and the IoT technology.

In order to enable a base station to obtain downlink channel quality, aUser Equipment (UE) reports Channel State Information (CSI) to the basestation. CSI reporting includes periodic CSI reporting and aperiodic CSIreporting. The periodic CSI reporting is performed according to a periodand a time offset configured via higher layer signaling. The aperiodicCSI reporting is driven by CSI request information in Downlink ControlInformation (DCI) on a Physical Uplink Shared Channel (PUSCH) that isscheduled by the base station. The UE transmits an aperiodic CSI reportto the base station of a serving cell according to an indication of theCSI request information. The CSI described herein may include a ChannelQuality Indicator (CQI), a Precoding Matrix Indicator (PMI), a RankIndicator (RI), and the like.

In addition, generally the channel state information also includesinformation representing a semi-static/long-term state of a channel,such as a Reference Signal Received Power (RSRP), a Reference SignalReceived Quality (RSRQ), and a Reference Signal-Signal to Noise andInterference Ratio (RS-SINR), a Received Signal Strength Indicator(RSSI). Typically, such information is used for cell selection, cellhandover, coverage level selection, and the like.

3GPP has standardized two narrowband systems for Internet of Things(IoT) in Rel13, i.e., an enhanced Machine Type Communication (eMTC)system and a Narrow Band Internet of Things (NB-IoT) system. In acoverage mode A, the eMTC system supports both periodic reporting andaperiodic CSI reporting in a connected state, while the NB-IoT systemdoes not support any CSI reporting. In addition, the eMTC system and theNB-IoT system select coverage levels based on RSRP. However, many IoTservices remain in a connected state for a short time. Therefore, inorder to better allocate downlink resources for an IoT UE according to achannel state, how to report the channel state more effectively is aproblem that needs to be solved, especially for uplinks of the NB-IoTsystem which only use Narrowband PUSCH (NPUSCH) to transmit uplink dataand uplink control information.

DISCLOSURE OF INVENTION Technical Problem

In order to better allocate downlink resources for an IoT UE accordingto a channel state, how to report the channel state more effectively isa problem that needs to be solved.

Solution to Problem

In a first aspect, the present disclosure provides a method for CSIreporting. The method includes: receiving configuration information forCSI reporting from a base station; triggering CSI reporting according toa CSI reporting trigger condition, wherein the CSI reporting triggercondition includes at least one of: a UE receiving the configurationinformation for CSI reporting, the UE receiving CSI reporting indicationinformation, a CSI variation of currently acquired CSI relative to CSIpreviously reported to the base station exceeding a predefined orpreconfigured condition, and the currently acquired CSI exceeding acertain threshold; and transmitting an uplink data channel carrying theCSI according to a predefined rule.

In an exemplary embodiment, the method further includes: after theconfiguration information for CSI reporting is received from the basestation or after the CSI reporting is triggered according to the CSIreporting trigger condition, determining resources for measuring the CSIbased on at least one of:

a capability of the UE to measure the CSI on measurement resources aftertransmitting a random access channel,

a capability of the UE to measure the CSI on measurement resources on anon-anchor carrier,

a capability of the UE to perform the CSI reporting on a non-anchorcarrier,

the configuration information configured by the base station for the CSIreporting,

information indicated by the base station in a Random Access Response(RAR).

In an exemplary embodiment, the carried CSI is CSI corresponding to allor a part of frequency domain resources in resources determined by theUE for measuring the CSI.

In an exemplary embodiment, the CSI corresponding to all or the part ofthe frequency domain resources in the resources for measuring the CSI isCSI calculated or selected or derived by the UE by assuming transmissionon all or the part of the frequency domain resources in the resourcesfor measuring the CSI.

In an exemplary embodiment, the resource for measuring the CSI may beCSI reference resources in an existing mechanism.

In an exemplary embodiment, the resources for measuring the CSI includeat least one of:

an anchor carrier,

a narrowband or a Physical Resource Block ‘PRB’ or a carrier on which adownlink control channel for RAR is received,

a narrowband or a PRB or a carrier on which a downlink data channel forRAR is received,

a narrowband or a PRB or a carrier on which paging is monitored,

frequency domain resources indicated in the configuration informationconfigured by the base station for the CSI reporting,

frequency domain resources indicated in the RAR by the base station,

predefined resources for measuring the CSI.

In an exemplary embodiment, the CSI includes at least one of: a CQI, aPMI, an RI, an RSRP, an RSRQ, an RS-SINR, an RSSI, and an indication ofa number of repetitions required to decode or detect a downlink channel.

In an exemplary embodiment, the indication of the number of repetitionsrequired to decode or detect the downlink channel further includes: anumber of repetitions satisfying decoding with a particular block errorrate, or a ratio or a difference between the number of repetitionssatisfying decoding with the particular block error rate and a currentlyconfigured number of repetitions.

In an exemplary embodiment, the operation of receiving the configurationinformation for CSI reporting from the base station further includes:receiving the configuration information for CSI reporting from the basestation via a Radio Resource Control (RRC) signaling.

In an exemplary embodiment, the RRC signaling is system information.

In an exemplary embodiment, the configuration information includes atleast one of:

resource information for CSI measurement, a number of repetitions of theresource for CSI measurement, a filter parameter for CSI measurement, aCSI measurement period, the CSI reporting trigger condition, a CSIindication range, resources for a random access channel indicating acapability of the UE to perform CSI reporting, and time-frequencyresources for CSI reporting.

In an exemplary embodiment, the resource information for CSI measurementincludes at least one of: physical time-frequency resource informationfor CSI measurement, reference signal information for CSI measurement,reference signal information for measuring intra-cell interference, andreference signal information for measuring inter-cell interference.

In an exemplary embodiment, after the configuration information for CSIreporting is received via the RRC signaling, the method furtherincludes: performing CSI measurement periodically according to theconfiguration information.

In an exemplary embodiment, the operation of receiving the configurationinformation for CSI reporting from the base station further includes:for each of one or more coverage levels and/or resources for a randomaccess channel, receiving the configuration information for CSIreporting from the base station.

In an exemplary embodiment, the CSI reporting indication informationreceived by the UE is transmitted in a Random Access Response (RAR) orconfigured by system information.

In an exemplary embodiment, the uplink data channel is an uplink datachannel for carrying an Msg3 message.

In an exemplary embodiment, the operation of transmitting the uplinkdata channel carrying the CSI according to the predefined rule furtherincludes: transmitting the CSI in one of:

a Media Access Control (MAC) sub-header in Msg3 corresponding to aCommon

Control CHannel (CCCH),

a MAC Control Element (CE) or a new MAC CE, and

an RRC message carried by the uplink data channel, wherein the RRCmessage is at least one of:

an RRC connection request message,

an RRC connection resume request message, and

an RRC connection re-establishment request message.

In an exemplary embodiment, said transmitting the uplink data channelcarrying the CSI according to the predefined rule further includes:indicating whether Uplink Control Information (UCI) is carried on theuplink data channel by at least one of:

a pattern and/or a sequence of pilot signals of the uplink data channel,

a Radio Network Temporary Identifier (RNTI) for scrambling the uplinkdata channel,

an indication field in a MAC header or a MAC sub-header or an RRCmessage,

wherein the pilot signal of the uplink data channel includes aDemodulation

Reference Signal (DMRS), and the UCI includes the CSI.

wherein the sequence of pilot signals of the uplink data channel furtherincludes a cyclic shift of the sequence of pilot signals.

In an exemplary embodiment, the information for indicating whether theUCI is carried on the uplink data channel is configured by the basestation through RRC signaling or is pre-defined.

In an exemplary embodiment, the CSI is mapped to the uplink data channelby means of piggyback.

In an exemplary embodiment, the operation of transmitting the uplinkdata channel carrying the CSI according to the predefined rule furtherincludes:

if ACK/NACK information needs to be transmitted at the same time,firstly mapping the ACK/NACK information to a Resource Element (RE)which is closest to a Reference Signal (RS), then and replacing a partof encoded and modulated uplink data channel data information with theCSI, for sequentially mapping to REs which are not occupied by theACK/NACK information or the RS; or

otherwise, replacing the part of the encoded and modulated uplink datachannel data information with the CSI, for sequentially mapping to REswhich are not occupied by the ACK/NACK information or the RS.

In an exemplary embodiment, the operation of mapping the CSI on theuplink data channel according to the predefined rule further includes:mapping and/or repeating the CSI and/or the ACK/NACK information on theuplink data channel on a per transport block or per RE basis.

In a second aspect, the present disclosure provides a method for CSIreporting. The method includes: configuring a UE with configurationinformation for CSI reporting; transmitting an RAR to the UE in responseto a random access request transmitted by the UE; and receiving anuplink data channel carrying CSI and obtaining the CSI according to apredefined rule.

In an exemplary embodiment, the RAR includes CSI reporting indicationinformation.

In an exemplary embodiment, the CSI includes at least one of: a CQI, aPMI, an RI, an RSRP, an RSRQ, an RS-SINR, an RSSI, and an indication ofa number of repetitions required to decode or detect a downlink channel.

In an exemplary embodiment, the indication of the number of repetitionsrequired to decode or detect the downlink channel further includes: anumber of repetitions satisfying decoding with a particular block errorrate, or a ratio or a difference between the number of repetitionssatisfying decoding with the particular block error rate and a currentlyconfigured number of repetitions.

In an exemplary embodiment, the configuration information includes atleast one of: resource information for CSI measurement, a number ofrepetitions of the resource for CSI measurement, a filter parameter forCSI measurement, a CSI measurement period, the CSI reporting triggercondition, a CSI indication range, resources for a random access channelindicating a capability of the UE to perform CSI reporting, andtime-frequency resources for CSI reporting.

In an exemplary embodiment, the operation of configuring the UE with theconfiguration information for CSI reporting further includes: for eachof one or more coverage levels and/or resources for a random accesschannel, configuring the UE with the configuration information for CSIreporting.

In an exemplary embodiment, the uplink data channel is an uplink datachannel for carrying an Msg3 message.

In an exemplary embodiment, the receiving the uplink data channelcarrying the CSI further includes: receiving the CSI in one of:

a MAC sub-header in Msg3 corresponding to a CCCH,

a MAC CE or a new MAC CE, and

an RRC message carried by the uplink data channel, where the RRC messageis at least one of:

an RRC connection request message,

an RRC connection resume request message, and

an RRC connection re-establishment request message.

In an exemplary embodiment, the CSI is mapped to the uplink data channelby means of piggyback.

In a third aspect, the present disclosure provides a UE. The UEincludes:

a processor; and

a memory storing computer-executable instructions that, when executed bythe processor, cause the processor to perform the method according tothe first aspect of the present disclosure.

In a fourth aspect, the present disclosure provides a base station. Thebase station includes:

a processor; and

a memory storing computer-executable instructions that, when executed bythe processor, cause the processor to perform the method according tothe second aspect of the present disclosure.

In a fifth aspect, the present disclosure provides a computer-readablemedium having stored thereon instructions that, when executed by aprocessor, cause the processor to perform the method according to thefirst aspect of the present disclosure.

In a sixth aspect, the present disclosure provides a computer-readablemedium having stored thereon instructions that, when executed by aprocessor, cause the processor to perform the method according to thesecond aspect of the present disclosure.

Advantageous Effects of Invention

According to various embodiments of the disclosure, reporting of channelstate information can be efficiently enhanced and allocation of downlinkresources for an IoT UE can be developed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 schematically shows an exemplary wireless communication system towhich the exemplary embodiments of the present disclosure may beapplied;

FIG. 2 schematically shows a flowchart of a method for CSI reporting ata UE according to an exemplary embodiment of the present disclosure;

FIG. 3 schematically shows a structure diagram of a UE according to anexemplary embodiment of the present disclosure;

FIG. 4 schematically shows a flowchart of a method for CSI reporting ata base station according to an exemplary embodiment of the presentdisclosure;

FIG. 5 schematically shows a structure diagram of a base stationaccording to an exemplary embodiment of the present disclosure;

FIG. 6 schematically shows a signaling sequence for CSI reportingbetween a base station and a UE according to an exemplary embodiment ofthe present disclosure;

FIG. 7 schematically shows a diagram of CSI reporting in MAC CEs;

FIG. 8 schematically shows another diagram of CSI reporting in MAC CEs;

FIG. 9 schematically shows a diagram in which CSI is piggybacked onPUSCH for transmission;

FIG. 10 schematically shows another diagram in which CSI is piggybackedon PUSCH for transmission;

FIG. 11 schematically shows yet another diagram in which CSI ispiggybacked on PUSCH for transmission;

FIG. 12 schematically shows an example of indicating whether CSI iscarried by an uplink data channel using a pilot signal of the uplinkdata channel;

FIG. 13 schematically shows a flowchart of a method for CSI reporting ata UE according to another exemplary embodiment of the presentdisclosure; and

FIG. 14 schematically shows a flowchart of a method for CSI reporting ata UE according to yet another exemplary embodiment of the presentdisclosure.

MODE FOR THE INVENTION

Embodiments of the present disclosure are described in detail below,examples of which are illustrated in the accompanying drawings, in whichthe same or similar reference numbers denote the same or similarelements or elements having the same or similar functions throughout.The embodiments described below with reference to the drawings areexemplary for explaining the present disclosure only, and should not beconstrued as limiting the present disclosure.

It will be understood by the skilled in the art that singular forms “a”,“an”, “said” and “the” used herein may also include plural forms, unlessspecifically stated. It should be further understood that the word“comprising” used in the description of the present disclosure refers topresence of features, integers, steps, operations, elements, and/orcomponents, but does not exclude presence or addition of one or moreother features, Integers, steps, operations, elements, components,and/or combinations thereof. It should be understood that when anelement is referred to as being “connected” or “coupled” to anotherelement, it can be directly connected or coupled to the other element,or there may also be intermediate elements. In addition, “connected” or“coupled” as used herein may include wirelessly connected or wirelesslycoupled. As used herein, the phrase “and/or” includes all or any of oneor more of associated listed items, and all of combinations thereof.

It may be understood by the skilled in the art that, unless definedotherwise, all terms (including technical and scientific terms) usedherein have the same meaning as commonly understood by the skilled inthe art to which the present disclosure belongs. It should also beunderstood that the terms such as those defined in a general dictionaryshould be understood as having a meaning that is consistent with that inthe context of the prior art, and will not be explained with anidealized or too formal meaning, unless specifically defined herein.

The skilled in the art may understand that the “UE” and “terminal” usedherein include not only a wireless signal receiver device, which is adevice only having a wireless signal receiver without a transmittingcapability, but also a device with receiving and transmitting hardware,which is a device having receiving and transmitting hardware capable ofperforming a bidirectional communication over a bidirectionalcommunication link. Such a device may include: a cellular or othercommunication device having a single line display or a multi-linedisplay or a cellular or other communication device without a multi-linedisplay; a Personal Communication Service (PCS), which may combinevoice, data processing, fax and/or data communication capabilities; aPersonal Digital Assistant (PDA), which may include a Radio Frequency(RF) receiver, a pager, Internet/Intranet access, a web browser, anotepad, a calendar, and/or a Global Positioning System (GPS) receiver;a conventional laptop and/or palmtop computer or other device, which maybe a conventional laptop and/or palmtop computer or other device havingand/or including an RF receiver. The “terminal”, “terminal device” asused herein may be portable, transportable, installed in a vehicle (ofaviation, maritime, and/or land), or may be adapted and/or configured tooperate locally, and/or may operate in a distributed form on the earthand/or at any other locations in space. The “UE” and “terminal” usedherein may also be a communication terminal, an Internet terminal, amusic/video playing terminal, such as a PDA, a Mobile Internet Device(MID), and/or a mobile phone having a music/video playback function, ora smart TV, a set-top box and other devices. In addition, “UE” and“terminal” may also be replaced with “user” and “UE”.

FIG. 1 shows an exemplary wireless communication system 100 according toan exemplary embodiment of the present disclosure. In FIG. 1, a UEdetects indication information. The wireless communication system 100includes one or more fixed infrastructure base units, forming a networkwhich is distributed over a geographic area. The base unit may also bereferred to as an Access Point (AP), an Access Terminal (AT), a BaseStation (BS), a Node-B, and an evolved NodeB (eNB), a next generation BS(gNB), or other terms used in the art. As shown in FIG. 1, one or morebase units 101 and 102 provide services for several Mobile Stations(MSs) or UEs or terminal devices or users 103 and 104 in a service area.For example, the service area may be a cell or a cell section. In somesystems, one or more BSs may be communicatively coupled to a controllerforming an access network, and the controller may be communicativelycoupled to one or more core networks. Examples in the present disclosureare not limited to any of particular wireless communication systems.

In a time and/or frequency domain, the base units 101 and 102 transmitdownlink communication signals 112 and 113 to the UEs 103 and 104,respectively. The UEs 103 and 104 communicate with one or more baseunits 101 and 102 via uplink communication signals 111 and 114,respectively. In one embodiment, the mobile communication system 100 isan Orthogonal Frequency Division Multiplexing (OFDM)/OrthogonalFrequency Division Multiple Access (OFDMA) system including a pluralityof base stations and a plurality of UEs. The plurality of base stationsinclude the base station 101, the base station 102, and the plurality ofUEs include the UE 103 and the UE 104. The base station 101 communicateswith the UE 103 through the uplink communication signal 111 and thedownlink communication signal 112. When the base station has a downlinkpacket to be transmitted to UEs, each UE may obtain a downlinkallocation (resource), such as a set of radio resources in a PhysicalDownlink Shared Channel (PDSCH) or a Narrowband Downlink Shared Channel(NPDSCH). When the UE needs to transmit a packet to the base station inthe uplink, the UE obtains an authorization from the base station, wherethe authorization allocates Physical Uplink Shared Channel (PUSCH) orNarrowband Uplink Shared Channel (NPUSCH) containing a set of uplinkradio resources. The UE obtains downlink or uplink schedulinginformation from a Physical Downlink Control Channel (PDCCH), or MPDCCH,or EPDCCH or NPDCCH dedicated to itself. Hereinafter, PDSCH, PDCCH,PUSCH are used to replace the above channels. The downlink or uplinkscheduling information and other control information carried on thedownlink control channel are referred to as Downlink Control Information(DCI). FIG. 1 also shows different physical channels, such as downlink112 and uplink 111. The downlink 112 includes a PDCCH or EPDCCH orNPDCCH or MPDCCH 121, a PDSCH or NPDSCH 122, a Physical ControlFormation Indicator Channel (PCFICH) 123, a Physical Multicast Channel(PMCH) 124, a Physical Broadcast Channel (PBCH) or a Narrowband PhysicalBroadcast Channel (NPBCH) 125, a Physical Hybrid Automatic RepeatRequest Indicator Channel (PHICH) 126, and a Primary SynchronizationSignal (PSS), a Secondary Synchronization Signal (SSS), or a NarrowbandPrimary Synchronization Signal/Secondary Synchronization Signal(NPSS/NSSS) 127. The downlink control channel 121 transmits a downlinkcontrol signal to the user. The DCI 120 is carried on the downlinkcontrol channel 121. The PDSCH 122 transmits data information to the UE.The PCFICH 123 transmits information for decoding PDCCH, e.g.dynamically indicating the number of symbols used by the PDCCH 121. PMCH124 carries broadcast multicast information. The PBCH or NPBCH 125carries a Master Information Block (MIB) for UE early discovery andcell-wide coverage. The PHICH carries Hybrid Automatic Repeat reQuest(HARQ) information that indicates whether the base station has correctlyreceived the uplink transmission signal. The uplink 111 includes aPhysical Uplink Control Channel (PUCCH) 131 which carries Uplink ControlInformation (UCI) 130, a PUSCH 132 which carries uplink datainformation, and a Physical Random Access Channel (PRACH) 133 thatcarries random access information. In the NB-IoT system, no NPUCCH isdefined, and NPUSCH Format 2 is used for transmitting the UCI 130.

In one embodiment, the wireless communication network 100 uses an OFDMAor multi-carrier architecture, including Adaptive Modulation and Coding(AMC) on downlink and a next-generation single-carrier FDMA architectureor multi-carrier OFDMA architecture for uplink transmission. TheFDMA-based single-carrier architecture includes Discrete FourierTransform-Spread Orthogonal Frequency Division Multiplexing (DFT-SOFDM)of Interleaved Frequency Division Multiple Access (IFDMA), LocalizedFDMA (LFDMA), IFDMA, or LFDMA, and also includes various enhancedNon-Orthogonal Multiple Access (NOMA) architectures of an OFDMA system,e.g., Pattern Division Multiple Access (PDMA), Sparse Code MultipleAccess (SCMA), Multi-User Shared Access (MUSA), Low Code Rate SpreadingFrequency Domain Spreading (LCRS FDS), Non-Orthogonal Coded MultipleAccess (NCMA), Resource Spreading Multiple Access (RSMA), InterleaveGridMultiple Access (IGMA), Low Density Spreading With Signature VectorExtension (LDS-SVE), Low code rate and Signature based Shared Access(LSSA), Non-Orthogonal Coded Access (NOCA), Interleave Division MultipleAccess (IDMA), Repetition Division Multiple Access (RDMA), GroupOrthogonal Coded Access (GOCA), Welch-bound equality based Spread MA(WSMA), etc.

In the OFDMA system, a remote unit is served by allocating downlink oruplink radio resources that typically include a set of subcarriers onone or more OFDM symbols. Exemplary OFDMA protocols include LTE evolvedfrom 3GPP UMTS standards and IEEE 802.16 standards. The architecture mayalso include the use of transmission technologies, such as Multi-CarrierCDMA (MC-CDMA), Multi-Carrier Direct Sequence CDMA (MC-DS-CDMA), andOrthogonal Frequency and Code Division Multiplexing (OFCDM) inone-dimensional or two-dimensional transmission, or may be based on asimpler time and/or frequency division multiplexing/multiple accesstechnology, or a combination of these different technologies. In analternative embodiment, the communication system may use other cellularcommunication system protocols, including but not limited to TDMA ordirect sequence CDMA.

In the NB-IoT system and the eMTC system, the UE performs downlinkmeasurement of RSRP and compares the downlink measurement result with athreshold value broadcasted by the base station in a System InformationBlock (SIB), selects a coverage level of the corresponding NPRACH/PRACH,and performs a random access process. For the eMTC system, a coverageenhancement format A (small-area coverage enhancement), an eMTC UE (alsoreferred to as a Bandwidth reduction and Low cost (BL)/CoverageEnhancement (CE) UE) supports CQI reporting. The base station configuresa number R^(CSI) of repetitions for the UE by an RRC parametercsi-NumRepetitionCE to extend a range of SINR. When a code rate andspectral efficiency are calculated, it is multiplied by the base stationconfiguration and then is compared with the code rate/spectralefficiency in a CQI table. For wideband CSI reporting, the UE determinesby calculation that time domain resources used by CSI areceil(R^(CSI)/N_(NB,hop) ^(ch,DL)) subframes before the referencesubframe, i.e., BL/CE downlink or special subframes for MPDCCH sensingon each narrow band (wherein, the BL/CE downlink or special subframesare predefined according to a protocol or configured according to RRC ofthe base station), where N_(NB,hop) ^(ch,DL) is a number of the narrowbands for sensing the MPDCCH by the BL/CE UE. For sub-band CSIreporting, the UE measures and deduces a value of CSI and reports it tothe base station according to R^(CSI) BL/CE downlink or specialsubframes for sensing the MPDCCH before the reference subframe on thecorresponding sub-band. In addition, the eMTC only supports periodic oraperiodic RRC reporting according to the RRC configuration of the basestation after it is in the connected state. Also, the eMTC supportsreporting of other information, such as RSRP and RSRQ, which mayrepresent the CQI, for handover. However, in a non-connected state, theCSI reporting cannot be performed.

In the current NB-IOT system, when the UE performs an initial access, itmay select corresponding NPRACH resource configuration according tocomparison between the measured downlink RSRP value andRSRP-ThresholdsNPRACH-InfoList. Here, the numbers of NPRACH repetitionsunder different NPRACH resource configurations will be different.RSRP-ThresholdsNPRACH-InfoList is a parameter broadcasted in the SIB andincludes two RSRP thresholds, that is, it can be divided into threelevels according to the downlink RSRP value, respectively correspondingto up to three NPRACH resource configurations. Considering that adownlink coupling path loss and an uplink coupling path loss are closeto each other, the downlink CE level determined according to thedownlink RSRP value may also be used in the uplink to determine thenumber of NPRACH repetitions.

After receiving the NPRACH, the eNB will determine the number of theMsg2/Msg4 NPDCCH repetitions according to the corresponding downlinkRSRP value. However in a practical system, decoding performance of theNPDCCH is determined by a downlink SINR, and the number of NPDCCHrepetitions determined according to the downlink RSRP value may notmatch the actual SINR. In addition, there are only three levels for thedownlink RSRP value derived by the eNB according to the received Msg1,which is thus of a greater probability of not matching the actual SINR.For example, the number of Msg2/Msg4 NPDCCH repetitions may beinsufficient, which may result in successful reception of Msg1 butunsuccessful reception of Msg2/Msg4, and eventually the NPRACH processis not successful; or the number of Msg2/Msg4 NPDCCH repetitions may beexcessive, which may result in waste of resources. If the UE may reporta value for representing a downlink interference quantity, such asRS-SINR, in Msg3, the eNB may select a more accurate number ofrepetitions for Msg4 NPDCCH, improving a success probability of theNPRACH process and optimizing system resources. In addition, the eNB mayconfigure, for the UE, a maximum number of repetitions Rmax required fora search space specific to the UE in Msg4.

Hereinafter, a flowchart of a method for CSI reporting at a UE accordingto an exemplary embodiment of the present disclosure will be describedin detail with reference to FIG. 2.

FIG. 2 schematically shows a flowchart of a method 200 for CSI reportingat a UE according to an exemplary embodiment of the present disclosure.As shown in FIG. 2, the method 200 may include:

step 201, in which the UE may receive configuration information for CSIreporting from a base station;

step 202, in which the UE may trigger CSI reporting according to a CSIreporting trigger condition; and

step 203, in which the UE transmits an uplink data channel carrying theCSI according to a predefined rule.

For an IoT system or other communication systems, such as NB-IoT, eMTC,etc., the CSI may include at least one of: a CQI, a PMI, an RI, an RSRP,an RSRQ, an RS-SINR, an RSSI, and an indication of a number ofrepetitions required to decode or detect a downlink channel.

The CSI may further include CSI reflecting the transmission on the Nnarrowbands/PRBs/carriers (N is a positive integer greater than or equalto 1), the CSI being calculated or selected or derived by the UEaccording to assuming transmission on the N narrowbands/PRBs/carriers inthe CSI reference resources. Specifically, the CSI may further include awideband CQI and/or a subband CQI in the existing mechanism.

In an exemplary embodiment, the CSI content or parameter reported by theUE is predefined, and/or is configured by the base station through theRRC signaling. Specifically, the UE receives the configurationinformation for the CSI reporting that is configured by the base stationthrough RRC, and if the content or the parameter of the CSI reporting inthe configuration information (which may be the configurationinformation corresponding to the coverage enhancement mode of the UE) isobtained, the UE reports the CSI content or parameter configured by thebase station; otherwise, the UE reports the predefined CSI content orparameter (which may be the predefined CSI content or parametercorresponding to the coverage enhancement mode of the UE, for example,the predefined CSI corresponding to the coverage enhancement mode A canbe the CQI, and the predefined CSI corresponding to the coverageenhancement mode B can be the indication of the number of repetitionsrequired to decode or detect the downlink channel).

In an exemplary embodiment, the downlink may be PDCCH or PDSCH or PBCH.Accordingly, the indication of the number of repetitions required todecode or detect the PDCCH or PDSCH or PBCH may further include: anumber of repetitions satisfying decoding with a particular block errorrate (BLER), or a ratio or a difference between the number ofrepetitions satisfying decoding with the particular BLER and a currentlyconfigured number of repetitions.

In step 201, the UE may receive the configuration information for CSIreporting from the base station via RRC signaling. In an exemplaryembodiment, the RRC signaling may be system information, i.e., the UEmay obtain the configuration information for CSI reporting by the systeminformation.

The configuration information may include at least one of: resourceinformation for CSI measurement (e.g., information on CSI referenceresources), a number of repetitions of the resource for CSI measurement,a filter parameter for CSI measurement, a CSI measurement period, theCSI reporting trigger condition, a CSI indication range, resources for arandom access channel indicating a capability of the UE to perform CSIreporting, and time-frequency resources for CSI reporting.

The resource information for CSI measurement includes: physicaltime-frequency resource information for CSI measurement (e.g., timedomain and frequency domain positions of a PRB or a PRB group), orreference signal information for CSI measurement (e.g., NRS, CSI-RS,CRS, DMRS, etc.), or physical channels for CSI measurement (e.g., PDCCH,PDCCH, PBCH, etc.).

In an exemplary embodiment, the physical time-frequency resourceinformation for CSI measurement includes physical time-frequencyresource location information of pilot resources used for CSImeasurement (e.g., carrier position and/or subframe position formeasuring the NRS). The number of repetitions of resources for CSImeasurement may be indicated in the system information, and/or may beinformation on a maximum number of repetitions (Rmax) in theconfiguration information of the search space (Type 2 Common SearchSpace, Type-2 CSS) for the random access response. Further, the numberof repetitions of resources for CSI measurement may be a minimum of apredefined number of repetitions and the number of repetitions for CSImeasurement indicated by the base station: The Number of Repetitions ofResources for CSI Measurement R^(CSI)=min (Predefined Number ofRepetitions, Configured Number of Repetitions (e.g., Rmax or Ws'configured in the SIB). Alternatively, the number of repetitions ofresources for CSI measurement may be selected by the UE autonomouslyfrom the predefined number of repetitions and the number of repetitionsfor CSI measurements indicated by the base station.

The configuration information further includes indication of the CSIcontent or parameter to be reported. The content or parameter of thereported CSI may be indicated in a CSI indication range. For example, 1bit is used for indicating that the UE reports the CQI or an indicationof the number of repetitions required to decode or detect the downlinkchannel. For example, 1 bit is used for indicating that the UE reportsthe subband CQI or the wideband CQI in the existing mechanism, or it isassumed that the UE reports the wideband CQI in the existing mechanismby default and 1 bit is used for indicating whether the UE additionallyreports the CQI reflecting the transmission on a narrowband (and thefrequency domain position of the narrowband). Further, the configurationinformation may be an indication of a predefined CSI reporting mode,e.g., indicating a CQI reporting mode (Mode 1-0, Mode 1-1, Mode 2-0,etc.) in the prior art.

When the configuration information does not include information of thecontent or parameter of the reported CSI, the UE reports the predefinedCSI content or parameter.

In addition, in order to better represent the SINR, resource informationfor CSI measurement may further include: reference signal informationfor measuring intra-cell interference, reference signal information formeasuring inter-cell interference.

For the periodic CSI reporting configured by RRC, the UE may perform CSImeasurement periodically according to the configuration information,after the configuration information for CSI reporting is received viathe RRC signaling.

For the aperiodic CSI reporting configured by the RRC, the UE may alsoperform CSI measurement periodically according to the configurationinformation, after the configuration information for CSI reporting isreceived via the RRC signaling.

Specifically, the UE may perform the CSI measurement periodically and/orperform the CSI measurement when a predefined condition is met,according to the physical time-frequency resource information for theCSI measurement in the configuration information for the CSI reporting,and when the aperiodic CSI reporting is being performed, the lastmeasured CSI is reported. In an exemplary embodiment, the base stationconfigures periodically occurring paging occasions for the UE, and theUE performs the periodic CSI measurement according to the monitoring ofthe paging occasion. In an exemplary embodiment, the predefinedcondition includes at least one of: the UE being required to perform theadditional CSI measurement according to the physical frequency domainresources for the CSI measurement which are configured in theconfiguration information for the CSI reporting; the given parameter inthe configuration information for the CSI reporting exceeding or fallingbelow a threshold which is predefined or configured by the base station.In an exemplary embodiment, the UE needs to perform the additional CSImeasurement, according to that the physical frequency domain resourcesfor the CSI measurement which are configured in the configurationinformation for the CSI reporting is not the narrowband on which the RARis received, or is not the narrowband used by the UE to monitor thedownlink control channel MPDCCH, or is not the anchor carrier, and/or isnot the non-anchor carrier on which the paging occasion is monitored.

For the NB-IoT system and the eMTC system, the base station mayconfigure a plurality of coverage levels for the PRACH. For example, theNB-IoT system may be configured with up to three coverage levels, andthe eMTC system may be configured with up to four coverage levels. Sincechannel conditions corresponding to different coverage levels aredifferent, the base station may configure different configurationinformation for different coverage levels and/or different PRACHresources. Accordingly, the UE may receive, from the base station,configuration information for CSI reporting for each of one or morecoverage levels and/or resources for the random access channel.Specifically, the base station may configure different CSI indicationranges (such as configuring the CSI as CQI or the number of repetitionsrequired to decode or detect the downlink channel, or configuring valuesof CSI corresponding to four states indicated by 2 bits), etc.

For the eMTC system, a plurality of coverage levels configured by thebase station for the PRACH may correspond to different coverageenhancement formats. In addition, the base station may also configuredifferent coverage enhancement formats for the UE. The coverageenhancement formats include a coverage enhancement format A (a smallerrange coverage enhancement) and a coverage enhancement format B (alarger range coverage enhancement). Since different channel conditionscorrespond to the different coverage enhancement formats, the basestation may configure different configuration information for differentcoverage enhancement formats, and/or the UE may report different CSIaccording to the different coverage enhancement formats. In an exemplaryembodiment, the base station may configure configuration information forreporting the CQI for the coverage enhancement format A, and configuresconfiguration information for reporting the number of repetitionsrequired to decode or detect the downlink channel for the coverageenhancement format B. Correspondingly, with the coverage enhancementformat A, the UE receives the configuration information for reportingthe CQI from the base station and performs the CQI reporting; and withthe coverage enhancement format B, the UE receives the configurationinformation for reporting the number of repetitions required to decodeor detect the downlink channel from the base station. In anotherexemplary embodiment, the predefined CSI reporting with the coverageenhancement formats A and B is reporting the number of repetitionsrequired to decode or detect the downlink channel, and the base stationconfigures to enable the reporting of the CQI for the coverageenhancement format A, and/or the configuration information for reportingthe CQI. Correspondingly, with coverage enhancement format A, the UEreceives the configuration information for reporting the CQI from thebase station and reports the CQI; and with the coverage enhancementformat B, the UE reports the number of repetitions required to decode ordetect the downlink channel according to the predefined configurationinformation and/or the configuration information configured by the basestation for the CSI reporting.

In step 202, the UE may trigger the CSI reporting according to the CSIreporting trigger condition. The CSI reporting trigger condition mayinclude at least one of: the UE receiving the configuration informationfor CSI reporting, the UE receiving CSI reporting indicationinformation, a CSI variation of currently acquired CSI compared to theprevious CSI reported to the base station exceeding a predefined orconfigured condition, and the currently acquired CSI exceeding a certainthreshold.

For the trigger condition for CSI reporting in Msg3, its reportingindication information is transmitted in the RAR. Alternatively, itsreporting indication information is configured by the systeminformation. Specifically, if the base station enables or configures aconfiguration parameter for CSI, it is a trigger condition of the CSIreporting.

In step 203, the uplink data channel for transmitting and carrying theCSI may be a PUSCH.

In an exemplary embodiment, the PUSCH may be a PUSCH for carrying Msg3.The above CSI reporting may be used in a contention-based random accessprocess and/or a non-contention random access process.

In particular, the CSI reporting may be performed before establishmentof the RRC connection.

Specifically, the UE may transmit the CSI by mapping to one of: an MACsub-header in Msg3 corresponding to a CCCH, a padding field or anadditional MAC sub-header of the MAC header in Msg3, a MAC CE (or a newMAC CE), and an RRC message.

The MAC CE may be at least one of the existing MAC CEs, such as a MAC CEfor DPR (Data Volume and Power Headroom Report)/PHR (Power HeadroomReport)/BSR (Buffer Status Report), in which the reserved bits can beused or the currently used bits can be occupied for indicating the CSI.Alternatively, a new MAC CE can be used, for example, a MAC CE forcarrying the CSI can be introduced.

The MAC CE is identified by a MAC sub-header with an LCID (LogicalChannel ID). The LCID is an LCID reserved in the existing mechanism(e.g., 01011-01111 or in the non-NB-IoT system, or 11101 in the NB-IoTsystem);

The length of the MAC CE is fixed to 0, that is, the CSI is indicated inthe sub-header of the MAC CE; or the length of the MAC CE is a fixednon-zero length or a variable length determined according to thereported CSI content, and the MAC CE including one or more CSI fieldssequentially indicates one or more pieces of CSI information, and/or aCSI quantity field is used to indicate the number of pieces of CSIreported in the MAC CE.

The RRC message may be at least one of: an RRC connection requestmessage, an RRC connection resume request message, and an RRC connectionre-establishment request message.

In another exemplary embodiment, the UE may map the CSI on the uplinkdata channel (e.g., PUSCH) by means of piggyback. That is, the CSI isreported through a physical layer, rather than being placed in the Msg3message. Further, for transmission of PUSCH and/or CSI required to berepeated (i.e., the number of repetitions is larger than or equal to 1),Transport Blocks (TBs) carried on CSI and PUSCH are repeated for thesame times, or the number of repetitions of the CSI is configured byRRC, and the CSI is piggybacked on the PUSCH for transmission.

In an exemplary embodiment, the transmitting the uplink data channelcarrying the CSI according to the predefined rule further includes: ifACK/NACK information needs to be transmitted at the same time, firstlymapping the ACK/NACK information to an RE which is closest to an RS, andthen replacing encoded and modulated partial uplink data channel datainformation with the CSI, for sequentially mapping to REs which are notoccupied by the ACK/NACK information or the RS; otherwise, replacing theencoded and modulated partial uplink data channel data information withthe CSI, for sequentially mapping to REs which are not occupied by theACK/NACK information or the RS.

Further, the mapping the CSI on the uplink data channel according to thepredefined rule further includes: mapping and/or repeating the CSIand/or the ACK/NACK information on the uplink data channel on a per TBor per RE basis.

Hereinafter, a structure of a UE according to an exemplary embodiment ofthe present disclosure will be described with reference to FIG. 3. FIG.3 schematically shows a structure block diagram of a UE 300 according toan exemplary embodiment of the present disclosure. The UE 300 may beused to perform the method 200 described with reference to FIG. 2. Forthe sake of brevity, only a schematic structure of the UE according tothe exemplary embodiment of the present disclosure will be describedherein, and the details which have been described in the method 200 withreference to FIG. 2 will thus be omitted.

As shown in FIG. 3, the UE 300 includes a processing unit or a processor301, which may be a single unit or a combination of multiple units forperforming different steps of the method; a memory 302 storingcomputer-executable instructions which, when executed by the processor301, cause the processor 302 to perform operations of: receivingconfiguration information for CSI reporting from a base station;triggering CSI reporting according to a CSI reporting trigger condition,wherein the CSI reporting trigger condition includes at least one of: aUE receiving the configuration information for CSI reporting, the UEreceiving CSI reporting indication information, a CSI variation ofcurrently acquired CSI relative to CSI previously reported to the basestation exceeding a predefined or configured condition, and thecurrently acquired CSI exceeding a certain threshold; and transmittingan uplink data channel carrying the CSI according to a predefined rule.

In an exemplary embodiment, the CSI includes at least one of: a CQI, aPMI, an RI, an RSRP, an RSRQ, an RS-SINR, an RSSI, and an indication ofa number of repetitions required to decode or detect a downlink channel.

In an exemplary embodiment, the CSI further includes at least one of:CSI corresponding to the transmission on all of frequency domainresources in the CSI reference resources, CSI corresponding to thetransmission on the selected frequency domain resources (which may be anabsolute value or a difference from the reference CSI, for example, adifference between the CSI corresponding to the transmission on theselected frequency domain resources and the reference CSI when the CSIcorresponding to the transmission on the CSI reference resources is thereference CSI), or the frequency domain position of the selectedfrequency domain resources. The CSI reference resources are frequencydomain resources for the UE to perform the CSI measurement which arereceived from the base station through the RRC signaling, and/or the CSIreference resources defined in the existing mechanism, and/or thepredefined frequency domain resources, and/or the frequency domainresources determined by the UE autonomously (for example, all of thefrequency domain resources for sensing the downlink control channelPDCCH by the UE).

The selected frequency domain resources are preferred frequency domainresources selected by the UE autonomously from all the monitoredfrequency domain resources or all the frequency domain resources of theCSI reference resources according to the channel quality, or thefrequency domain resources configured by the base station through theRRC signaling. The frequency domain position of the selected frequencydomain resources is an absolute frequency domain position (e.g., anindex of the narrowband/(sub)PRB/(sub)carrier), or a relative positionof the selected frequency domain resources in all the CSI referenceresources. For example, when all the CSI reference resources include 4narrowbands, and the selected frequency domain resources include 1narrowband, 2 bits are used to indicate that the relative position ofthe partial CSI reference resource in all the CSI reference resources isthe first/second/third/fourth narrowband.

Specifically, the CSI further includes at least one of CSI calculated orselected or derived according to the conditions of: assumingtransmission on all of the frequency domain resources in the CSIreference resources; the UE selecting M preferred frequency resources(e.g., M=1) from the set of all the frequency domain resources in whichthe control channel PDCCH is transmitted, and a reported CSI valuereflecting the transmission on only one or M selected frequency domainresources, wherein the frequency domain resource in the CSI referenceresources includes a narrowband or (sub)PRB or (sub)carrier.

In an exemplary embodiment, the indication of the number of repetitionsrequired to decode or detect the downlink channel further includes: anumber of repetitions satisfying decoding with a particular BLER, or aratio or a difference between the number of repetitions satisfyingdecoding with the particular BLER and a current configured number ofrepetitions. The required number of repetitions is not obtained bymeasurement, but it is derived by the UE with a hypothesis via measuringthe RS or a predefined physical resource. Specifically, the current basestation configures a maximum number of PDCCH repetitions Rmax1 for theUE, but the UE calculates the required number of repetitions to be nolarger than Rmax1/b by measuring the RS, then the UE reports acoefficient b; or, if b is greater than x, the UE reports it, where bbeing greater than x is used as the trigger reporting condition, x maybe predefined in the protocol or configured in the CSI reportingconfiguration information to the UE. For another example, in MSG3, thenumber of repetitions required by the UE to satisfy a specific BLER isindicated by 2 bits, as shown in Table 1. The 2 bits respectivelyindicate four states {Rmax, Rmax/4, Rmax/2, 2Rmax}, wherein 00 is usedto represent Rmax (that is, no adjustment or no reporting is required),and is also used to represent a UE that does not support this function;for the base station, if it receives 00, it is considered (temporarily)that the maximum number of PDCCH repetitions Rmax is not necessary to beadjusted, and wherein Rmax is the number of PDCCH repetitions configuredin the search space for RAR/MSG3 retransmission and MSG4 transmission inthe coverage level corresponding to the random access of the UE, or Rmaxmay be configured by the base station. For example, the base station mayconfigure a reference number of repetitions Rmax′ for each coveragelevel separately to construct an indication of CSI reporting. If Rmax istoo small, rounding may be performed, and there will be a plurality ofstates representing that their numbers of repetitions are 1. Further,when Rmax=2, Rmax/4=0.5 may represent that a PDCCH Aggregation Level(AL) is only required to be 1. For example, Table 2 shows the number ofrepetitions that each state represents for different Rmax values. Itshould be noted that when Rmax>1, AL=2. Similarly, a finer channel statemay be indicated by 3 bits. In this case, the UE that does not supportthe characteristic may be indicated separately, for example, by 000″. Inanother example, a table may be defined that directly representsabsolute values independent of Rmax or the reference number ofrepetitions Rmax′.

Since the base station may determine whether this function is actuallysupported based on UE capability in the connected state, the basestation may determine, based on the UE capability, whether the status“00” actually represents that Rmax is not necessary to be adjusted (thatis, the current Rmax is an Rmax required to satisfy 1% BLER), orrepresents that the UE has no measurement to be reported.

TABLE 1 Number Of Repetitions Of DCI Subfame CSI 00 This Function Notsupported orRmax 01 Rmax/4 10 Rmax/2 11 2Rmax

TABLE 2 Number Of Rep- etitions Of DCI CSI Subfame Rmax = 1 Rmax = 2Rmax > 2 00 This Function This Function This Function Not supported NotNot supported supportedorAL = orAL = 2, RL = 2 2, RL = Rmax 01 AL = 1,RL = 1 AL = 1, RL = 1 AL = 2, RL = Rmax/4 10 AL = 2, RL = 1 AL = 2, RL =1 AL = 2, RL = Rmax/2 11 AL = 2, RL = 2 AL = 2, RL = 4 AL = 2, RL =2Rmax

In an exemplary embodiment, the operation of receiving the configurationinformation for CSI reporting from the base station further includes:receiving the configuration information for CSI reporting from the basestation via RRC signaling.

In an exemplary embodiment, the RRC signaling is system information.

In an exemplary embodiment, the configuration information includes atleast one of: resource information for CSI measurement, a number ofrepetitions of the resource for CSI measurement, a filter parameter forCSI measurement, a CSI measurement period, the CSI reporting triggercondition, a CSI indication range, resources for a random access channelindicating a capability of the UE to perform CSI reporting, andtime-frequency resources for CSI reporting.

In an exemplary embodiment, after the configuration information for CSIreporting is received via the RRC signaling, the method furtherincludes: performing CSI measurement periodically according to theconfiguration information.

In an exemplary embodiment, the receiving the configuration informationfor CSI reporting from the base station further includes: for each ofone or more coverage levels and/or resources for a random accesschannel, receiving the configuration information for CSI reporting fromthe base station.

In an exemplary embodiment, the CSI reporting indication informationreceived by the UE is transmitted in an RAR. Specifically, 1 bit in theCSI request field of the RAR is used to indicate the CSI reportingindication information. Alternatively, the CSI reporting indicationinformation is configured by the system information. Specifically, ifthe base station enables (including activating by a specific signalingdisplay) or configures the configuration parameters used for CSI(implicitly activating by optional configuration parameters used forconfiguring the CSI), this is a trigger condition of the CSI reporting.

In an exemplary embodiment, the CSI reporting indication informationreceived by the UE is indicated in the RAR and the system message.Specifically, if the base station enables (including explicitly enablingby a specific signaling) or configures the configuration parameter forthe CSI, and the RAR received by the UE includes the CSI reportingindication information (for example, the CSI request domain in the RARindicates the CSI reporting), this is the trigger condition of the CSIreporting. Specifically, if the UE has the capability of performing theCSI reporting in the Msg3, and the base station enables (includingexplicitly enabling by a specific signaling) or configures theconfiguration parameter for the CSI reporting or indicates that the basestation supports the characteristic of carrying the CSI reporting in theMsg3, the CSI request field in the RAR grant message received by the UEis not reserved in the contention-based random access procedure. For theUE, when the CSI request field in the RAR Grant is set to trigger asingle reporting and the field is not reserved, the UE performs theaperiodic CSI reporting.

In an exemplary embodiment, the uplink data channel is an uplink datachannel for carrying an Msg3 message.

In an exemplary embodiment, the transmitting the uplink data channelcarrying the CSI according to the predefined rule further includes:transmitting the CSI in one of:

a MAC sub-header in Msg3 corresponding to a CCCH,

a MAC CE or a new MAC CE, and

an RRC message carried by the uplink data channel, wherein the RRCmessage is at least one of:

an RRC connection request message,

an RRC connection resume request message, and

an RRC connection re-establishment request message.

In an exemplary embodiment, the CSI is mapped to the uplink data channelby means of piggyback.

In an exemplary embodiment, the operation of transmitting the uplinkdata channel carrying the CSI according to the predefined rule furtherincludes:

if ACK/NACK information needs to be transmitted at the same time,firstly mapping the ACK/NACK information to an RE which is closest to anRS, and then replacing encoded and modulated partial uplink data channeldata information with the CSI, for sequentially mapping to REs which arenot occupied by the ACK/NACK information or the RS; or

otherwise, replacing the encoded and modulated partial uplink datachannel data information with the CSI, for sequentially mapping to REswhich are not occupied by the ACK/NACK information or the RS.

Further, the operation of mapping the CSI on the uplink data channelaccording to the predefined rule further includes: mapping and/orrepeating the CSI and/or the ACK/NACK information on the uplink datachannel on a per transport block or per RE basis.

Hereinafter, a flowchart of a method for CSI reporting at a base stationaccording to an exemplary embodiment of the present disclosure will bedescribed in detail with reference to FIG. 4.

FIG. 4 schematically shows a flowchart of a method 400 for CSI reportingat a UE according to an exemplary embodiment of the present disclosure.As shown in FIG. 4, the method 400 may include:

step 401, in which the base station configures a UE with configurationinformation for CSI reporting;

step 402, in which the base station transmits an RAR to the UE inresponse to a random access request transmitted by the UE; and

step 403, in which the base station receives an uplink data channelcarrying CSI and obtaining the CSI according to a predefined rule.

In step 402, the RAR includes CSI reporting indication information.

In an exemplary embodiment, the CSI includes at least one of: a CQI, aPMI, an RI, an RSRP, an RSRQ, an RS-SINR, an RSSI, and an indication ofa number of repetitions required to decode or detect a downlink channel.

In an exemplary embodiment, the indication of the number of repetitionsrequired to decode or detect the downlink channel further includes: anumber of repetitions satisfying decoding with a particular BLER, or aratio or a difference between the number of repetitions satisfyingdecoding with the particular BLER and a currently configured number ofrepetitions.

In an exemplary embodiment, the configuration information configured inStep 401 for the UE includes at least one of: resource information forCSI measurement, a number of repetitions of the resource for CSImeasurement, a filter parameter for CSI measurement, a CSI measurementperiod, the CSI reporting trigger condition, a CSI indication range(including the content or parameter of the reported CSI), resources fora random access channel indicating a capability of the UE to perform CSIreporting, and time-frequency resources for CSI reporting.

In an exemplary embodiment, the operation of configuring the UE with theconfiguration information for CSI reporting in step 401 furtherincludes: for each of one or more coverage levels and/or resources for arandom access channel, configuring the UE with the configurationinformation for CSI reporting, and further includes: for each of one ormore coverage enhancement modes, configuring the UE with theconfiguration information for CSI reporting.

In an exemplary embodiment, the uplink data channel is an uplink datachannel for carrying an Msg3 message.

In an exemplary embodiment, the operation of receiving the uplink datachannel carrying the CSI in step 403 further includes: receiving the CSIin one of:

a MAC sub-header in Msg3 corresponding to a CCCH,

a padding field or an additional MAC sub-header of the MAC header inMsg3,

a MAC CE or a new MAC CE, and

an RRC message carried by the uplink data channel, where the RRC messageis at least one of: an RRC connection request message, an RRC connectionresume request message, and an RRC connection re-establishment requestmessage.

In an exemplary embodiment, the CSI is mapped to the uplink data channelby means of piggyback.

In an exemplary embodiment, it is indicated whether Uplink ControlInformation (UCI) is carried on the uplink data channel by at least oneof: a pattern and/or a sequence of pilot signals of the uplink datachannel, an RNTI for scrambling the uplink data channel, an indicationfield in a MAC header or a MAC sub-header or an RRC message (e.g., a CSIindication field of 1 bit). The pilot signal of the uplink data channelincludes a DMRS, and the UCI includes the CSI. Further, theconfiguration information configured for the UE in step 401 includes theat least one of information for indicating whether the UCI is carried onthe uplink data channel.

Hereinafter, a structure of a base station according to an exemplaryembodiment of the present disclosure will be described with reference toFIG. 5. FIG. 5 schematically shows a structure block diagram of a basestation 500 according to an exemplary embodiment of the presentdisclosure. The base station 500 may be used to perform the method 400described with reference to FIG. 4. For the sake of brevity, only aschematic structure of the base station according to the exemplaryembodiment of the present disclosure will be described herein, and thedetails which have been described in the method 400 with reference toFIG. 4 will thus be omitted.

As shown in FIG. 5, the base station 500 includes a processing unit or aprocessor 501, which may be a single unit or a combination of multipleunits for performing different steps of the method; a memory 502 storingcomputer-executable instructions which, when executed by the processor501, cause the processor 502 to perform operations of: configuring a UEwith configuration information for CSI reporting; transmitting an RAR tothe UE in response to a random access request transmitted by the UE; andreceiving an uplink data channel carrying CSI and obtaining the CSIaccording to a predefined rule.

In an exemplary embodiment, the CSI includes at least one of: a CQI, aPMI, an RI, an RSRP, an RSRQ, an RS-SINR, an RSSI, and an indication ofa number of repetitions required to decode or detect a downlink channel.

In an exemplary embodiment, the indication of the number of repetitionsrequired to decode or detect the downlink channel further includes: anumber of repetitions satisfying decoding with a particular BLER, or aratio or a difference between the number of repetitions satisfyingdecoding with the particular BLER and a currently configured number ofrepetitions.

In an exemplary embodiment, the configuration information includes atleast one of: resource information for CSI measurement, a number ofrepetitions of the resource for CSI measurement, a filter parameter forCSI measurement, a CSI measurement period, the CSI reporting triggercondition, a CSI indication range, resources for a random access channelindicating a capability of the UE to perform CSI reporting, andtime-frequency resources for CSI reporting.

In an exemplary embodiment, the operation of configuring the UE with theconfiguration information for CSI reporting further includes: for eachof one or more coverage levels and/or resources for a random accesschannel, configuring the UE with the configuration information for CSIreporting.

In an exemplary embodiment, the uplink data channel is an uplink datachannel for carrying an Msg3 message.

In an exemplary embodiment, the receiving the uplink data channelcarrying the CSI further includes: receiving the CSI in one of:

a MAC sub-header in Msg3 corresponding to a CCCH,

a MAC CE or a new MAC CE, and

an RRC message carried by the uplink data channel, where the RRC messageis at least one of: an RRC connection request message, an RRC connectionresume request message, and an RRC connection re-establishment requestmessage.

In an exemplary embodiment, the CSI is mapped to the uplink data channelby means of piggyback.

FIG. 6 schematically shows a signaling sequence for CSI reportingbetween a base station and a UE according to an exemplary embodiment ofthe present disclosure. As shown in FIG. 6, the UE receivesconfiguration information for CSI reporting which is configured by thebase station by means of system information; the UE transmits a randomaccess request to the base station; the UE receives an RAR, includingchannel status indication information (i.e., CSI reporting indicationinformation); the UE transmits a Msg (Message) 3 and carries CSI in theMsg3, or piggybacks the CSI on a PUSCH carrying the Msg3. In anotherembodiment, for some purposes (for example, one or more of followingrequests: an RRC connection request message, an RRC connection resumerequest message, an RRC connection re-establishment request message; theUE being out of synchronization in the connected state; a random accessprocess being triggered by the base station; a random access process forhandover) or all purposes, or for only contention-based ornon-contention-based random access, it is not necessary to indicate theCSI reporting indication information by the RAR; and if the base stationconfigures the configuration information for CSI reporting in the systeminformation (that is, implicitly indicating the CSI reportinginformation), the CSI reporting is performed by default.

Correspondingly, the base station configures the configurationinformation for CSI reporting to the UE by the system information; thebase station receives a random access request transmitted by the UE; thebase station transmits an RAR including a CSI reporting indication; thebase station receives the Msg3 transmitted by the UE and receives CSIwhich is in Msg3 or is piggybacked on the PUSCH carrying the Msg3; thebase station selects suitable a RRC parameter for the UE according tothe CSI and/or the base station performs suitable downlink schedulingfor the UE according to the CSI.

The CSI includes at least one of: a CQI, a PMI, an RI, an RSRP, an RSRQ,an RS-SINR and an RSSI, or other information which may represent thechannel state, e.g., an indication of a number of repetitions requiredto decode following channel at a specific BLER (such as 1% or 10%):PDCCH, PDSCH (PDSCH based on a configured or given bit rate or spectralefficiency), PBCH, wherein the specific BLER may be configured by thebase station to the UE, or predefined in the protocol; or a number ofrepetitions of the current configuration being greater or less than therequired number of repetitions or a certain multiple (e.g. ½ or 2 or xtimes) of the required number of repetitions, in which case, the CSI maybe indicated by less bit information, such as 1 to 3 bits, wherein thecertain multiple may be configured by the base station to the UE orpredefined in the protocol (as shown in Table 1 or Table 2). Inaddition, in this case, the information may be deduced from a long-termstatistical channel state (e.g., RS-SINR), but is not deduced from aspecific subframe (set) (e.g., CQI). The long-term statistical channelstate may be calculated according to L3-filter. Alternatively, the basestation configures a larger number of repetitions R^(CSI), so as toobtain a relatively stable indication value that may represent the CSI.

Further, the base station may configure parameters for CSI reportingrespectively for different PRACH/NPRACH coverage levels. Specifically,for example, the number of repetitions R^(CSI) for CQI calculation maybe configured as different values for different coverage levels. Foranother example, the filter parameter, a parameter range ofRSRQ/RSRP/RS-SINR/RSSI etc., or a type, etc., may also be respectivelyconfigured for different coverage levels. Specific parameters for on-CSIreporting may refer to parameters configured for different CSI in TS316.331 or TS 38.331.

In an example, the RSRQ/RSRP/RS-SINR/RSSI value reported in Msg3 is theresult of L3-filter. The UE may perform the L3-filter processing on theSINR measurement result according to the following formula, where M_(n)is the latest result measured by the physical layer, F_(n−1) is theresult of the last L3-filter processing, and F_(n) is the result of thelatest L3-filter processing.F _(n)=(1−a)*F _(n−1) ±a*M _(n)

A forgetting factor of the above L3-filter is a=½ (k/4), and k is anL3-filter coefficient (FilterCoefficient). In an example,FilterCoefficient is fixed at 4, that is, a=½; in another example,FilterCoefficient is configured by the SIB as follows. If there is noindication, a default value 4, i.e., a=½, is used.

FilterCoefficient::=ENUMERATED {fc0, fc1, fc2, fc3, fc4, fc5, fc6, fc7,fc8, fc9, fc11, fc13, fc15, fc17, fc19, spare1, . . . }

For the parameter range of RSRQ/RSRP/RS-SINR/RSSI etc., the existingrange may be reused, or different SINR ranges may be configured fordifferent coverage levels, so as to reduce signaling and reportingoverhead. Specifically, for example, here rssinr-Result reuses theexisting RS-SINR-Range-r13, that is, 7 bits are used to indicate thequantized values of 128 values.

RS-SINR-Range-r13::=INTEGER(0 . . . 127)

In another example, rs-sinr-Result is indicated with fewer bits, e.g.SINR is quantized to 8 levels, indicated with 3 bits, thereby saving thesignaling overhead.

Some previous versions of legacy UEs cannot have this CSI reportingcapability. The base station may configure a separate PRACH resource forthe UE having this CSI reporting capability. For the UE supporting thisCSI reporting capability, it may be determined by reading the systeminformation configured by the base station whether the base station/cellenables a CSI reporting function. For example, it may be determined byreading information of PRACH configuration whether there is a parameterof CSI reporting in the information of PRACH configuration, or whetherthere is a PRACH resource that is used separately to indicate thechannel status reporting capability, or whether the configurationinformation for CSI reporting is configured etc. If the cell enables theCSI reporting function, the UE selects the corresponding PRACH resourceto perform the random access request. The UE receives the RAR, andparses the content of the RAR according to a new format, such as whetherthere is a CSI reporting indication. For previous versions of the eMTCsystem or the LTE system, if it is a contention-based random accessrequest, the CSI reporting indication information will be ignored inparsing the content of the RAR. However in the scheme of the presentdisclosure, CSI may be reported for any contention-based random accessprocess, regardless of the RRC connected or the non-connected state.Therefore, if the UE determines that the base station/cell supports thenew CSI reporting capability, the eMTC or LTE UE parses the CSIreporting indication information in the RAR. In another example, the UEdoes not need to additionally parse whether there is CSI reportindication information in the RAR. As long as the base station enablesthis function, the CSI reporting is performed in the MSG 3 according toa predefined rule. For the NB-IoT system, reserved bit(s) in the RAR maybe set as the CSI reporting indication, and only the UE supporting thisfunction will make the parsing. In another example, whether the CSIreporting is needed to be performed may be indicated by different RNTIsfor indicating RAR scheduling. Alternatively, whether all or a part ofUEs corresponding to the RAR in this MAC PDU may be indicated (e.g., bybitmap) by reserved information in the MAC (sub) header in the RAR, orby a newly designed MAC CE. This new MAC CE may be placed at the end ofthis MAC PDU so as not to affect the legacy UE.

In an embodiment, all NB-IoT UEs must support reporting SINR or otherCSI information in Msg3, that is, reporting SINR or other CSIinformation in advance in Msg3 is a mandatory feature for the UE. Inanother embodiment, reporting SINR in advance in Msg3 is an optionalfeature for the UE, and only the UE supporting this function reports theSINR measurement result or other CSI information in Msg3. Thiscapability indication may also be indicated in Msg3, such as the first 7reserved bits in the RRCConnectionRequest-NB message being all 0,indicating that the UE does not support this function. If none of these7 reserved bits is 0, this indicates that the UE supports the function,and these 7 bits represent the reported SINR information or otherinformation. The reporting may also be performed by reserved bits lessthan 7 bits.

In one embodiment, all NB-IoT eNBs must support the function ofreporting CSI in Msg3. That is, reporting CSI in advance in Msg3 is amandatory feature for the eNB. In another embodiment, reporting SINR inadvance in Msg3 is an optional feature for the eNB, and only the UEsserved by the eNB that supports the function can report the CSImeasurement result in Msg3. The capability indication of the eNBsupporting this function may be broadcasted in the SIB. In order toreduce the signaling overhead, the eNB supporting this function may beimplicitly represented by configuring the configuration information forCSI reporting.

In an example, the UE may report the CSI in the Msg3 message.Specifically, the CSI reporting may be performed on the reserved bits inthe existing Msg3 message, for example, a MAC sub-header in Msg3corresponding to CCCH, or a Data Volume and Power Headroom Report (DPR)MAC CE (or a new MAC CE), or on spare bit(s) of an RRC message in an RRCconnection request message (RRCconnectionrequest)/RRC connection resumerequest message (ConnectionResumeRequest)/RRC connection reestablishmentrequest message (RRCconnectionReestablishmentRequest). It may beconfigured in the RRC with a fixed number of bits, such as 1-2 bits, orthe number of bits, or different numbers of bits may be used accordingto different types of messages. For being configured in the RRC, sparebits (redundant bits) in the existing RRCConnectionRequest informationare used to report the quantized SINR value, for example, using 7 sparebits.

The existing R13 RRCConnectionRequest-NB message consists of:

 RRCConnectionRequest-NB-r13-IEs ::= SEQUENCE {  ue-Identity-r13InitialUE-Identity,  establishmentCause-r13 EstablishmentCause-NB-r13,multiToneSupport-r13 ENUMERATED {true}  OPTIONAL, multiCarrierSupport-r13 ENUMERATED {true} OPTIONAL,  spare BIT STRING(SIZE (22))  }  The new R13 RRCConnectionRequest-NB message consists of: RRCConnectionRequest-NB-r13-IEs ::= SEQUENCE {  ue-Identity-r13InitialUE-Identity,  establishmentCause-r13 EstablishmentCause-NB-r13, multiToneSupport-r13 ENUMERATED {true} OPTIONAL, multiCarrierSupport-r13 ENUMERATED {true} OPTIONAL, rs-sinr-Result-t14, RS-SINR-Range-r14,  spare BIT STRING (SIZE (15))  }

In the current NB-IOT system, the UE reports the data volume and thepower headroom in the Msg3. The reporting approach is to place a DPR MACCE fixedly before the Msg3 CCCH SDU. The DPR MAC CE has 8 bits,including 2 reserved bits, 2 PH bits, and 4 DV bits. FIG. 7schematically shows a diagram of CSI reporting in MAC CEs. As shown inFIG. 7, based on the existing DPR MAC CE, the second reserved bit isoccupied by the CSI. When the information is 1 (or 0), it indicates thatthe current number of PDCCH repetitions may be adjusted to ½ (or onelevel lower); otherwise, it indicates that the current number of PDCCHrepetitions is appropriate. For example, “appropriate” may indicate thata specific BLER requirement (e.g., 1%) may be just met, and decreasingto an adjacent lower level will not meet the specific BLER requirement.In this example, the state in which the current number of PDCCHrepetitions cannot satisfy the specific BLER requirement is discarded.For situations that cannot meet the requirement, the UE may select thenext coverage level for random access. That is, when the UE selects thePRACH resources for random access, the UE needs to select based onwhether the number of PDCCH repetitions configured for the coveragelevel can meet the specific BLER requirement, in addition to selectingbased on the RSRP threshold configured by the base station. Withreference to a CQI calculation method, the BLER of the PDCCH may beobtained by deducing from the RS of the latest Rmax or Rmax/M downlinkor special subframes; or with reference to an RS-SINR calculationmethod, the decoding performance of the PDCCH may be deduced from theRS-SINR obtained by the base station configuring the filter coefficient,where Rmax is the maximum number of PDCCH repetitions, and M is acoefficient, which may be predefined or configured to the UE via RRC.

In addition, 2 bits may be occupied, and only four predefined CSI statesmay be reported.

Similarly, 1-2 bits on MAC CEs of the current Power Headroom Report(PHR) or Buffer Status Report (BSR) may be occupied for the CSIreporting.

In addition, in the existing NB-IoT system, the 2-bit Power Headroom(PH) field in the Msg3 supports only four levels of PH values (as shownin Table 3). It is too insufficient for the eNB to estimate a real UEPH. Thus, subsequent NPUSCH resource scheduling will be affected. Thatis because the NB-IOT UE uses open-loop power control for uplink datatransmission, and the remaining PH of the UE directly affects the amountof uplink physical resources that may be scheduled subsequently. If abit indication is added to the PH value reported in the Msg3, moreefficient uplink resource scheduling may be achieved.

In an embodiment, in order to maintain backward compatibility of thesystem, the UE uses 2 reserved bits in the existing DPR MAC CE and 2 PHbits together to indicate the reported PH value. The corresponding DPRMAC CE compositions are shown in FIG. 8. Here, 4 bits are used toindicate 16 PH values, as shown in Table 4.

TABLE 3 PH Power Headroom Level 0 POWER_HEADROOM_0 1 POWER_HEADROOM_1 2POWER_HEADROOM_2 3 POWER_HEADROOM_3

TABLE 4 PH Power Headroom Level 0 POWER_HEADROOM_0 1 POWER_HEADROOM_1 2POWER_HEADROOM_2 3 POWER_HEADROOM_3 14 POWER_HEADROOM_14 15POWER_HEADROOM_15

In another example, if a Transport Block Size (TBS) allocated for theMsg3 is large enough, the CSI may be reported in the PUSCH carrying theMsg3 as data or MAC CE. With reference to a process of BSR reporting, apriority may be predefined for the CSI reporting, for example, before orafter the BSR and/or PHR. The method of using MAC for CSI reporting asdescribed above is also applicable to instants other than the Msg3,which may be indicated by the DCI, or configured by the RRC (such asconfigured periodically), or indicated by the MAC CE (or MAC(sub)header). Alternatively, it may be triggered by a predefined event.For example, when there is a certain deviation between the CSIinformation and the previously reported CSI information, or the decodingof the current PDCCH or the PDSCH configured by some base station or thepredefined PDSCH (for example, a code rate or spectral efficiency)cannot satisfy a specific BLER, or the configured number of repetitionsexceeds or is less than a certain value or a certain multiple of thenumber of repetitions required to reach the code rate. The CSI reportedin the Msg3 may be triggered by the event, e.g., the PDCCH/or PDSCH (thePDSCH based on the configured or given code rate or spectral efficiency)configured by the base station is too large or too small. In this case,the base station may reconfigure the number of PDCCH and/or PDSCHrepetitions by the CSI message.

In another example, the UE may piggyback the CSI as Uplink ControlInformation (UCI) in the PUSCH carrying the Msg3. FIG. 9 shows anexample of UCI being piggybacked on the PUSCH for transmission. In orderto ensure the decoding performance, HARQ ACK/NACK (A/N) feedbackinformation is transmitted on the symbol closest to the RS, with RIbeing placed outside and CQI being placed before data information,occupying 16 REs, which are mapped into one PRB in an order of timedomain first and frequency domain next, wherein A/N, RI, and CQIpuncture the data information.

FIG. 10 is an example of UCI piggybacked on PUSCH transmission duringSub-PRB scheduling. For the Sub-PRB scheduling, such as the NB-IoTsystem or the eMTC system after Rel-15, the PUSCH supports the Sub-PRBscheduling, which defines Resource Units (RUs) with 1, 3 and 6subcarriers and time periods of 8 ms, 4 ms and 2 ms, respectively. FIG.10 shows an example in which the UCI is piggybacked on the PUSCH fortransmission when there are 6 subcarriers and a transmission duration of2 ms in one RU. Although the PUSCH is crossing 2 ms and 28 symbols,since only 6 subcarriers are occupied, the code rate of the PUSCH doesnot change. Since the occupied bandwidth of the PUSCH becomes smaller,the energy on each subcarrier becomes larger, that is, Power SpectralDensity (PSD) is boosting, which may improve the performance of the SNRat the receiving end, thereby improving the decoding performance.Therefore, in order to enable the UCI transmission to obtain theperformance matching with the PUSCH, similar with the whole PRBscheduling, the same encoding may be performed for the UCI, improvingthe decoding performance depending on PSD boosting. The CQI in FIG. 10is the same as that in FIG. 9, occupying 16 REs, and the A/N is also thesame as that in FIG. 9, occupying 12 REs. In addition, the A/N is stilltransmitted on the symbol as close as possible to the RS. Meanwhile, inorder to obtain a time diversity gain, the REs as discrete as possiblemay be selected for transmitting the A/N. As shown in FIG. 10, the A/Nmessages are first mapped to the REs closest to the RSs on the lowermostsubcarrier (which is opposite to the subcarrier starting the datamapping), and then mapped to the REs closest to the RSs on the secondsubcarrier subsequently. Similarly, when the PUSCH resources areallocated to a plurality of RUs, the A/Ns maps from the lowermostsubcarrier (which is opposite to the subcarrier starting the datamapping), until the next RU subsequently.

FIG. 11 is a schematic diagram of UCI being piggybacked on PUSCH fortransmission when 1 single tone resource is allocated. The rule thereofis similar with FIG. 9 and FIG. 10, i.e., mapping A/N information on thesymbol (i.e., RE) closest to the RS, then mapping the CQI before PUSCHdata information, and sequentially mapping to the REs not occupied bythe A/N or the RS. If there is no A/N, it is sequentially mapped to REsare not occupied by the RS. Specifically, for the A/N with a length of12 REs, symbols S2, S4, S9, S11, S16, S18, S23, S25, S30, S32, S37, andS39 are occupied. The CQI occupies 16 REs from S0 to S27 except the REsoccupied by the A/N and the RS. The data part starts mapping from S28,until it fills all scheduled resource blocks (except the A/N and theRS).

The examples in FIGS. 10 and 11 only give examples of the A/N and theCQI. Feedback to the RI may be placed on the symbol outside the A/Naccording to the rule of FIG. 9. Alternatively, it may follow the A/N,and continue to be mapped on the REs in accordance with the A/N rule.

In addition, regardless of how many subcarriers in one RU or one PRB,when the number of PUSCH repetitions is greater than 1, the UCI is alsorepeated following the PUSCH per one or more RUs, so as to ensure thatthe UCI may obtain a repetition gain equivalent to a repetition gain ofthe PUSCH.

When the base station decodes the PUSCH, since the UCI punctures thePUSCH transmission, it does not affect the PUSCH coherent detection. Thebase station can still perform coherent demodulation of the repeateddata of the two PUSCHs at the RE level to reduce the effect of noise andimprove the equivalent SNR at the receiver.

For the transmission of the CSI (as the UCI) piggybacked on the PUSCHcarrying the Msg3, since there are UEs that do not support suchreporting (such as the legacy UEs) and UEs that support such reportingin the system, different PRACH resources may be used for distinguishingthe two types of the UEs; otherwise, the base station cannot knowwhether the UCI is piggybacked on the PUSCH of the Msg3. Alternatively,the base station may perform blind detection on whether the UCI ispiggybacked on the PUSCH. For example, the information bits in the UCImay be encoded with CRC, and then the base station may confirm whetherthe UCI exists by using the CRC check. However, if the number of thebits in the UCI is smaller, the overhead of adding the CRC check bits istoo high. In order to reduce the overhead and reduce the blind detectioncomplexity of the base station, the UE may indicate to the base stationwhether the UCI is piggybacked on the PUSCH of the Msg3 by differentpilot signals (such as different pilot patterns and/or pilot sequences(including different sequences and different cyclic shifts)). The basestation may decide which of the PUSCH mapping is used for decoding theMsg3 and whether the detection of the UCI is needed by detecting thedifferent pilot signals.

In an exemplary embodiment, the transmitting of the uplink data channelcarrying the CSI according to the predefined rule further includes:indicating whether UCI is carried on the uplink data channel by at leastone of:

a pattern and/or a sequence of pilot signals of the uplink data channel,

an RNTI for scrambling the uplink data channel,

an indication field in a MAC header or a MAC sub-header or an RRCmessage,

wherein the pilot signal of the uplink data channel includes a DMRS, andthe UCI includes the CSI.

In an exemplary embodiment, the information for indicating whether theUCI is carried on the uplink data channel is configured by the basestation through RRC signaling or is pre-defined. Further, theinformation for indicating whether the UCI is carried on the uplink datachannel may be configured by the base station separately for each of oneor more coverage (enhancement) levels and/or random access channelresources and/or coverage enhancement modes, or predefined.Specifically, the RRC signaling may be system information.

Further, for the transmission of the uplink data channel of the Msg3whose number of repetitions is greater than or equal to 1, for eachrepetition or every Z repetitions, the at least one of the above is usedto indicate whether the UCI is carried on the uplink data channel, whereZ is a redundancy version cycling period.

FIG. 12 is an example of using a pilot signal of an uplink data channelfor indicating whether CSI is carried on the uplink data channel. Thepilot signal in this example may be a demodulation reference signalDMRS. The UE obtains information of the pilot signal for the CSIreporting which is indicated in the configuration information for theCSI reporting. The information of the pilot signal for the CSI reportingis used for indicating whether the UCI (including the CSI) is carried onthe uplink data channel, which may be a pattern or sequence of pilotsignals, or a method of generating the pattern/sequence of pilotsignals, or a predefined information required for the method ofgenerating the pattern/sequence of pilot signals (e.g., some parameterin a predefined calculation formula). When the CSI reporting is carriedin the Msg3, as shown in (b) of FIG. 12, the UE generates the uplinkshared channel PUSCH carrying the Msg3 according to the existingmechanism, replaces a part of the encoded and modulated data informationof the uplink data channel with the CSI, sequentially maps it to REsthat are not occupied by the ACK/NACK information or RS; and generatesthe pattern or sequence of pilot signals (e.g., Pilot Signal 2 in FIG.12) according to the information of the pilot signal for the CSIreporting, the pattern or sequence of pilot signals being mapped to theREs at the corresponding positions as the reference signal of the uplinkdata channel of the Msg3; otherwise, when the CSI reporting is notcarried in the Msg3, as shown in (a) of FIG. 12, the UE generates theuplink shared channel PUSCH carrying the Msg3 according to the existingmechanism, generates the reference signal of the uplink data channel ofthe Msg3 according to an existing mechanism (for example, Pilot Signal 1in FIG. 12, or the examples in FIGS. 9 to 11) and maps it to the REs atthe corresponding positions.

In another example, the UE acquires the RNTI configured by the basestation, including the RNTI in the existing mechanism and a new RNTI forthe CSI reporting. When the CSI reporting is carried in the Msg3, theuplink data channel of the Msg3 sent by the UE is scrambled by the newRNTI reported by the CSI; otherwise, when the CSI reporting is notcarried in the Msg3, the uplink data channel of the Msg3 sent by the UEis scrambled by the RNTI in the existing mechanism. The UE acquires thenew RNTI for the CSI reporting, including the new RNTI and/or theparameters for calculating the new RNTI indicated by the base station inthe configuration information for the CSI reporting and/or the randomaccess response RAR, and/or the RNTI determined by the UE according tothe predefined criteria and/or the configuration information of the basestation (including the configuration information for the CSI reportingand the information indicated in the random access response RAR), forexample, the UE calculates the new RNTI for the CSI reporting accordingto the temporary C-RNTI (TC-RNTI) indicated in the RAR.

In another example, the UE uses a 1-bit CSI indication field in the MACheader or MAC sub-header or RRC message to indicate whether the CSI iscarried on the uplink data channel.

In the existing MTC and NB-IoT systems, the UE may be scheduled by thebase station to different frequency domain resources(narrowbands/PRBs/carriers) for uplink transmission and downlinkreception. For this possibility, a method for reporting the CSI in theMsg3 is to enable the UE to report in the Msg3 the CSI related to thefrequency domain resources used in the subsequent downlink reception, sothat the CSI reported by the UE in the Msg3 is more valuable to thetransmission scheduled by the base station, and better reflects thechannel state of the subsequent downlink reception of the UE. Forexample, in an Early Data Transmission (EDT) scenario, the UE reports inthe Msg3 the CSI corresponding to the frequency domain resources of thedownlink control channel PDCCH and/or the downlink data channel PDSCHfor receiving the random access response RAR, or the UE reports in theMsg3 the CSI corresponding to the frequency domain resources of thePDCCH of the Msg3 (e.g. for scheduling the retransmission of the Msg3)and/or the PDCCH of the Msg4. For example, for a non-EDT scenario, theUE reports in the Msg3 the CSI corresponding to the frequency domainresources of the PDCCH and/or the PDSCH for receiving the random accessresponse RAR, or reports the CSI corresponding to the frequency domainresources monitored by the plurality of UEs, as the referenceinformation considered by the base station to which frequency domainresources the UE is scheduled for the downlink reception.

Another method for reporting the CSI in the Msg3 is to design frequencydomain resources corresponding to the reported CSI based on such a basiccriterion that in order to reduce the power consumption of the UE, thereported CSI won't cause additional CSI measurements compared to theexisting UE behavior. Therefore, the CSI reported by the UE is the CSIcorresponding to the frequency domain resources for monitoring ordownlink reception in the existing behavior (for example, the PDCCHand/or PDSCH for RAR, the narrowband/carrier/PRB on which the paging ismonitored, and the frequency domain resources for measuring RSRP/RSRQbefore the RACH is transmitted). Further, the UE may report one piece ofCSI or multiple pieces of CSI corresponding to multiple frequency domainpositions.

Hereinafter, specific descriptions of feasible technical solutionsrelated to the two methods will be provided.

In an exemplary embodiment, in step 203 of the method 200 for the CSIreporting performed at the UE side according to the exemplary embodimentof the present invention, the CSI carried on the uplink data channelsent by the UE according to a predefined rule may be corresponding tothe resources determined by the UE for measuring the CSI, andspecifically, corresponding to all or a part of the frequency domainresources in the resources for measuring the CSI.

The CSI corresponding to all or the part of the frequency domainresources in the resources for measuring the CSI is CSI calculated orselected or derived by the UE according to assuming transmission on allor the part of the frequency domain resources in the resources formeasuring the CSI.

The resources for measuring the CSI may be the CSI reference resourcesin the existing mechanism, and/or the resources for measuring the CSIare determined based on at least one of: the capability of the UE tomeasure the CSI on the measurement resources after transmitting therandom access channel (e.g., PRACH), the capability of the UE to measurethe CSI on the measurement resources of the non-anchor carrier, thecapability of the UE to perform the CSI reporting on the non-anchorcarrier, the configuration information configured by the base stationfor the CSI reporting, the information indicated by the base station inthe RAR, a predefined criterion. The number of frequency domainresources for measuring the resources of the CSI may be zero, that is,the UE determines that the CSI reporting in the Msg3 is not supported.

In another exemplary embodiment, as shown in FIG. 13, after the UEreceives the configuration information for indicating the CSI reportingfrom the base station in step 201, the UE may determine the resourcesfor the CSI according to the configuration information for indicatingthe CSI reporting, and/or the information in the RAR received in step1301 from the base station. Next, in step 202, the CSI reporting istriggered according to the CSI reporting trigger condition; then in step203, the uplink data channel carrying the CSI is transmitted accordingto the predefined rule.

In another exemplary embodiment, as shown in FIG. 14, the UE may receivethe configuration information for indicating the CSI reporting from thebase station in step 201; after triggering the CSI reporting accordingto the CSI reporting trigger condition in step 202, the UE may determinethe resources for measuring the CSI according to the configurationinformation for indicating the CSI reporting and/or the information inthe RAR received in step 1401 from the base station. Then in step 203,the uplink data channel carrying the CSI is transmitted according to thepredefined rule.

The resources for measuring the CSI may include at least one of: ananchor carrier, a narrowband or a PRB or a carrier on which a downlinkcontrol channel for RAR is received, a narrowband or a PRB or a carrieron which a downlink data channel for RAR is received, a narrowband or aPRB or a carrier on which paging is monitored, frequency domainresources indicated in the configuration information configured by thebase station for the CSI reporting, frequency domain resources indicatedin the RAR by the base station, predefined resources for measuring theCSI. The PRB or carrier in any of the above items may be a sub-PRB or asub-carrier. Further, if the frequency hopping of the channel or thefrequency domain resources corresponding to the resources for measuringthe CSI is enabled, the resources for measuring the CSI further includeall narrowbands or (sub)PRBs or (sub)carriers for the frequency hopping.

Further, if the frequency domain resources for measuring the CSI includethe non-anchor carrier, when the UE measures the CSI on the non-anchorcarrier of the resources for measuring the CSI, the UE performsoperations including at least one of: measuring the reference signalperiodically transmitted on the non-anchor carrier, measuring thereference signal from N1 subframes before the start of a search spacefor monitoring the RAR (for example, a Type-2 Common Search Space (CSS))and N2 subframes after the end of the search space, measuring thereference signal from the N3 subframes before the start of a searchspace for monitoring the paging and/or wakeup signal (WUS) to the N4subframes after the end of the search space.

Further, if the resources for measuring the CSI do not include anyfrequency domain resource, that is, the resource for measuring the CSIis empty, the UE does not report the CSI.

Additionally, it should be noted that the UE determining the resourcesfor measuring the CSI and the UE triggering the CSI reporting do nothave an absolute order in time. In an example, the UE determines theresources for measuring the CSI according to the configurationinformation for indicating the CSI reporting, and then triggers the CSIreporting by the information indicated in the RAR. In another example,the UE triggers the CSI reporting by the information indicated in theRAR, and then determines the resources for measuring the CSI accordingto the configuration information for indicating the CSI reporting andthe information indicated in the RAR.

In an exemplary embodiment, the UE determines the resources formeasuring the CSI according to at least one of: the predefinedcriterion, the capability of the UE to measure the CSI for reportingafter the RACH is transmitted, the configuration information for the CSIreporting configured by the base station, the information indicated bythe base station in the RAR. If the UE has the capability of measuringthe CSI for reporting after the RACH is transmitted, when the frequencydomain resources of the PDCCH of the Msg3/4 are indicated in the RARreceived by the UE (for example, the Msg3/4 MPDCCH narrowband indexfield is included in the RAR), according to the predefined criterionand/or the information indicated in the RAR, the resources for measuringthe CSI include at least one of: the narrowband or PRB or carrier forthe PDCCH of the Msg3/4 that indicated in the RAR, the narrowband or PRBor carrier on which the downlink control channel PDCCH for RAR isreceived, the narrowband or PRB or carrier on which the downlink datachannel PDSCH for RAR is received, or the frequency domain resources inthe configuration information configured by the base station for the CSIreporting. Otherwise, when the frequency domain resources of the PDCCHof the Msg3/4 are not indicated in the RAR received by the UE (forexample, the Msg3/4 MPDCCH narrowband index field is not included in theRAR), the resources for measuring the CSI include at least one of: thenarrowband or PRB or carrier on which the downlink control channel PDCCHfor RAR is received, the narrowband or PRB or carrier on which thedownlink data channel PDSCH for RAR is received, or the frequency domainresources in the configuration information configured by the basestation for the CSI reporting.

Otherwise, if the UE does not have the capability of measuring the CSIfor reporting after the RACH is transmitted, no matter whether thefrequency domain resources of the PDCCH of the Msg3/4 is indicated inthe RAR received by the UE, according to the predefined criterion, theresources for measuring the CSI include at least one of: the narrowbandor PRB or carrier on which the downlink control channel PDCCH for RAR isreceived, the narrowband or PRB or carrier on which the paging ismonitored, and the frequency domain resources in the configurationinformation configured by the base station for the CSI reporting, theanchor carrier.

In an exemplary embodiment, the UE determines the resources formeasuring the CSI according to at least one of: the predefinedcriterion, the capability of the UE to measure the CSI for reportingafter the RACH is transmitted, the capability of the UE to support theCSI reporting of the non-anchor carrier, or the configurationinformation for the CSI reporting configured by the base station. Forthe NB-IoT UE having the capability of measuring the CSI for reportingafter the RACH is transmitted and supporting the non-anchor carrier, theresources for measuring the CSI include: the carrier for the CSIreporting which is configured by the base station and/or predefined. Ifthe carrier meets at least one of the following conditions that thecarrier is a carrier of the PDCCH and/or PDSCH for RAR, that the carrieris the anchored Carrier, that the carrier is the non-anchor carrier onwhich the paging (including the anchor/non-anchor carrier for monitoringthe paging occasions of the NB-IoT UE itself and/or the paging occasionsof other UEs) is monitored, the base station configures the position ofthe NB-IoT reference signal NRS on the carrier, the UE can assume thatthere are NRSs available for measurement (e.g., periodically occurring)on the carrier.

In an example, if any of the carriers configured by the base station forthe CSI reporting does not meet any of the above conditions, or if thebase station does not configure a carrier for the CSI reporting, theresources for measuring the CSI is the carrier of the PDCCH and/or PDSCHfor RAR. In another example, if the base station configures the carrierfor the CSI reporting and the carrier meets at least one of the aboveconditions, the resources for measuring the CSI are the carrier.

Otherwise, for a UE that does not have the capability of measuring theCSI for reporting after the RACH is transmitted and has the capabilityof supporting the CSI reporting of the non-anchor carrier, the resourcesfor measuring the CSI include: the carrier for the CSI reporting whichis configured by the base station and/or predefined. If the carriermeets at least one of the following conditions that the carrier is theanchor carrier, that the carrier is the non-anchor carrier on which thepaging (including the anchor/non-anchor carrier for monitoring thepaging occasions of the UE itself and/or the paging occasions of otherUEs) is monitored, the base station configures the position of theNB-IoT reference signal NRS on the carrier, the UE can assume that thereare NRSs available for measurement (e.g., periodically occurred) on thecarrier.

In an example, if any of the carriers configured by the base station forthe CSI reporting does not meet any of the above conditions, or if thebase station does not configure a carrier for the CSI reporting, theresources for measuring the CSI is the anchor carrier and/or thenon-anchor carrier on which paging is monitored. In another example, ifthe base station configures the carrier for the CSI reporting and thecarrier meets at least one of the above conditions, the resources formeasuring the CSI are the carrier.

Further, for the CSI reporting in the random access procedure on thenon-anchor carrier, if the resources for measuring the CSI do notinclude any non-anchor carrier, according to the predefined criterion,the resource for measuring the CSI is the anchor carrier and the CSI ofthe anchor carrier is reported by the UE in the Msg3, or the CSIreporting is not performed by the UE in the Msg3.

Otherwise, for the UE that does not have the capability of supportingthe CSI reporting of the non-anchor carrier, according to the predefinedcriterion, the resource for measuring the CSI is the anchor carrier andthe CSI of the anchor carrier is reported by the UE in Msg3, or forrandom access on the anchor carrier, the existing mechanism can bereused, the CSI reporting is not performed by the UE in the Msg3 for therandom access UE on the non-anchor carrier.

In an exemplary embodiment, If the UE has the capability of measuringthe CSI for reporting after the RACH is transmitted, when the frequencydomain resources of the PDCCH of the Msg3/4 are indicated in the RARreceived by the UE (for example, the Msg3/4 MPDCCH narrowband indexfield is included in the RAR), the UE measures the CSI corresponding tothe narrowband or PRB or carrier for the PDCCH of the Msg3/4 thatindicated in the RAR, and reports the CSI in the Msg3. If the UEcompletes the CSI measurement before the Msg3 transmission time in theexisting mechanism, the UE transmits the Msg3 according to the time inthe existing mechanism; otherwise, the UE transmits the Msg3 accordingto a new transmission time which may be determined based on the maximumnumber of repetitions (for example, Rmax) in the configurationinformation for the CSI reporting. Specifically, when the maximum numberof repetitions in the configuration information for the CSI reportingdoes not exceed a given threshold, the UE transmits the Msg3 accordingto the time in the existing mechanism, otherwise the UE transmits theMsg3 according to the new transmission time.

Correspondingly, if the base station indicates the frequency domainresources of the PDCCH of the Msg3/4 in the RAR transmitted to the UE,the base station monitors the Msg3 transmitted by the UE at the time oftransmitting the Msg3 in the existing mechanism, and if it is notsuccessfully received, the base station monitors the Msg3 transmitted bythe UE at the new transmission time.

In an exemplary embodiment, when the base station supports the CSIreporting in the Msg3, the base station may schedule, in the RAR thattriggers the CSI reporting, a larger TBS for the UE than that in theexisting mechanism, wherein the redundant part of the TBS may be usedfor indicating the CSI information.

For the above examples, it should be additionally noted that whether theUE has the capability of measuring the CSI for reporting after the RACHis transmitted may be whether the UE has the capability of generatingthe Msg3 carrying the CSI after the RACH is transmitted. For example, ifthe UE has the capability of generating the Msg3 after the RACH istransmitted or has the capability of modifying the generated Msg3 tocarry the CSI (including carrying the CSI as the RRC layer messagefield, carrying the CSI as the MAC CE or field, carrying the CSI as thephysical layer information) after the RACH is transmitted, the UE may beconsidered to have the capability of measuring the CSI for reportingafter the RACH is transmitted; otherwise the UE may be considered not tohave the capability of measuring the CSI for reporting after the RACH istransmitted.

Computer-executable instructions or programs for implementing thefunctions of various embodiments of the present disclosure may berecorded on a computer-readable storage medium. Corresponding functionscan be realized by having a computer system read programs recorded onthe recording medium and execute these programs. The so-called “computersystem” herein may be a computer system embedded in the device, and mayinclude an operating system or hardware (such as a peripheral device).The “computer-readable storage medium” may be a semiconductor recordingmedium, an optical recording medium, a magnetic recording medium, ashort-time dynamic storage program recording medium, or any otherrecording media readable by a computer.

Various features or functional modules of the devices used in the aboveembodiments may be implemented or performed by circuitry (e.g., asingle-chip or multi-chip integrated circuit). Circuits designed toperform the functions described in the present specification may includegeneral purpose processors, digital signal processors (DSPs),application specific integrated circuits (ASICs), field programmablegate arrays (FPGAs), or other programmable logic devices, discrete Gateor transistor logic, discrete hardware components, or any combination ofthe above. A general-purpose processor may be a microprocessor or anyexisting processor, controller, microcontroller, or state machine. Theabove circuit may be a digital circuit or an analog circuit. In a caseof new integrated circuit technology that replaces existing integratedcircuits due to advances in semiconductor technology, one or moreembodiments of the present disclosure may also be implemented usingthese new integrated circuit technologies.

The skilled in the art will understand that the present disclosureincludes devices that are involved in performing one or more of theoperations described in the present disclosure. These devices may bespecially designed and manufactured for the required purposes, or mayalso include known devices in general purpose computers. These deviceshave computer programs stored thereon that are selectively activated orreconfigured. Such computer programs may be stored in a device (e.g., acomputer) readable medium or in any type of medium suitable for storingelectronic instructions and coupled to a bus, including but not limitedto any types of disks, including a floppy disk, a hard disk, an opticaldisk, a CD-ROM, and a magneto-optical disk, a ROM (Read-Only Memory), aRAM (Random Access Memory), an EPROM (EraSable Programmable Read-OnlyMemory), an EEPROM (Electrically Erasable Programmable Read-OnlyMemory), a flash memory, a magnetic card, or a light card. That is, areadable medium includes any medium that stores or transmits informationin a readable form by a device (e.g., a computer).

The skilled in the art can understand that each block of thesestructural diagrams and/or block diagrams and/or flowcharts, andcombinations of blocks in these structural diagrams and/or blockdiagrams and/or flowcharts may be implemented by computer programinstructions. The skilled in the art can understand that these computerprogram instructions can be provided to a processor of a general-purposecomputer, a professional computer, or a processor for other programmabledata processing method, so that the schemes specified in one or moreblocks of the structural diagrams and/or block diagrams and/orflowcharts may be executed by the processor of the computer or thecomputer for other programmable data processing method.

The skilled in the art can understand that various operations, methods,steps, measures, and schemes that have been discussed in the presentdisclosure can be alternated, changed, combined, or deleted. Further,various operations, methods that have been discussed in the presentdisclosure, and other steps, measures, and schemes in the process canalso be alternated, changed, rearranged, decomposed, combined, ordeleted. Further, various operations, methods, steps, measures, andschemes in the prior art and those disclosed in the present disclosuremay also be alternated, changed, rearranged, decomposed, combined, ordeleted.

The foregoing descriptions are merely some of the embodiments of thepresent disclosure. It should be noted that for the skilled in the art,a number of improvements and modifications may be made without departingfrom the principle of the present disclosure. These improvements andmodifications should also fall within the protection scope of thepresent disclosure.

The invention claimed is:
 1. A method performed by a terminal supportinga narrowband internet of things (NB-IoT) in a wireless communicationsystem, the method comprising: receiving, from a base station, a systeminformation block (SIB) including first information indicating a reportof downlink channel quality; generating a result of a downlink channelquality measurement performed based on the first information included inthe SIB; and transmitting, to the base station, a radio resource control(RRC) message which is a message 3 (MSG3) of a random access procedure,the RRC message including second information corresponding to theresult, wherein the second information includes a plurality of bitsindicating information on a minimum NB-IoT physical downlink controlchannel (NPDCCH) repetition level which satisfies a predetermined blockerror rate (BLER), wherein the plurality of bits being all 0 indicatesthat no information is reported for the downlink channel qualitymeasurement, and wherein a value of the plurality of bits other than all0 indicates the result.
 2. The method of claim 1, wherein the SIB isassociated with an NB-IoT system, and wherein the RRC message comprisesan RRC connection request message, an RRC connection resume requestmessage, or an RRC connection reestablishment request message.
 3. Themethod of claim 2, wherein a number of the plurality of bits isdifferent for different RRC messages.
 4. A method performed by a basestation supporting a narrowband internet of things (NB-IoT) in awireless communication system, the method comprising: transmitting, to aterminal, a system information block (SIB) including first informationindicating a report of downlink channel quality; and receiving, from theterminal, a radio resource control (RRC) message which is a message 3(MSG3) of a random access procedure, the RRC message including secondinformation corresponding to a result of a downlink channel qualitymeasurement based on the first information included in the SIB, whereinthe second information includes a plurality of bits indicatinginformation on a minimum NB-IoT physical downlink control channel(NPDCCH) repetition level which satisfies a predetermined block errorrate (BLER), wherein the plurality of bits being all 0 indicates that noinformation is reported for the downlink channel quality measurement,and wherein a value of the plurality of bits other than all 0 indicatesthe result.
 5. The method of claim 4, wherein the SIB is associated withan NB-IoT system, and wherein the RRC message comprises an RRCconnection request message, an RRC connection resume request message, oran RRC connection reestablishment request message.
 6. The method ofclaim 5, wherein a number of the plurality of bits is different fordifferent RRC messages.
 7. A terminal supporting a narrowband internetof things (NB-IoT) in a wireless communication system, the terminalcomprising: a transceiver configured to transmit or receive a signal;and a controller coupled with the transceiver and configured to:receive, from a base station, a system information block (SIB) includingfirst information indicating a report of downlink channel quality,generate a result of a downlink channel quality measurement performedbased on the first information included in the SIB, and transmit, to thebase station, a radio resource control (RRC) message which is a message3 (MSG3) of a random access procedure, the RRC message including secondinformation corresponding to the result, wherein the second informationincludes a plurality of bits indicating information on a minimum NB-IoTphysical downlink control channel (NPDCCH) repetition level whichsatisfies a predetermined block error rate (BLER), wherein the pluralityof bits being all 0 indicates that no information is reported for thedownlink channel quality measurement, and wherein a value of theplurality of bits other than all 0 indicates the result.
 8. The terminalof claim 7, wherein the SIB is associated with an NB-IoT system, andwherein the RRC message comprises an RRC connection request message, anRRC connection resume request message, or an RRC connectionreestablishment request message.
 9. The terminal of claim 8, wherein anumber of the plurality of bits is different for different RRC messages.10. A base station supporting a narrowband internet of things (NB-IoT)in a wireless communication system, the base station comprising: atransceiver configured to transmit or receive a signal; and a controllercoupled with the transceiver and configured to: transmit, to a terminal,a system information block (SIB) including first information indicatinga report of downlink channel quality, and receive, from the terminal, aradio resource control (RRC) message which is a message 3 (MSG3) of arandom access procedure, the RRC message including second informationcorresponding to a result of a downlink channel quality measurementbased on the first information included in the SIB, wherein the secondinformation includes a plurality of bits indicating information on aminimum NB-IoT physical downlink control channel (NPDCCH) repetitionlevel which satisfies a predetermined block error rate (BLER), whereinthe plurality of bits being all 0 indicates that no information isreported for the downlink channel quality measurement, and wherein avalue of the plurality of bits other than all 0 indicates the result.11. The base station of claim 10, wherein the SIB is associated with anNB-IoT system, and wherein the RRC message comprises an RRC connectionrequest message, an RRC connection resume request message, or an RRCconnection reestablishment request message.
 12. The base station ofclaim 10, wherein a number of the plurality of bits is different fordifferent RRC messages.